By

Bob Bartizek

Joe Lesser’s article in the last issue of the HiRailers Buzz about consists got me thinking more about the aspects of prototype railroading. The following information on prototypical railroad consists may be of interest to some HiRailers.

When building freight consists for your favorite road, it is fun to know what the mix of cars would have been in a particular train. This information is highly era-dependent, and I’m most familiar with the 1930’s to 1950’s. If your interests lie in modern railroading, you’ll need to rely on someone else.

Overall, the US freight car fleet in 1948 had the following percentages:

36% Boxcars (mostly single-door 40-foot)

31% Hopper Cars

8% Tank Cars

7% Refrigerator Cars

7% Gondolas

3% Stock Cars

3% Flat Cars

3% Automobile Boxcars (mostly double-door 50-foot)

1% Covered Hoppers

1% Other

Some large adjustments must be made for different regions of the country. For example, most of the hoppers were on eastern lines like the PRR, N&W, VGN, B&O, C&O, LV, etc. Western roads had only about 10% of the hoppers during this railroading era. Let’s ignore seasonal shipments such as fruit, vegetables, and cattle and focus on typical railroad consists.

Now, what road names do you include in your consist? How many “home road” cars should there be? It depends a lot on the railroad. I have some information listed below from 1944 that details the percentages of the home road and other road cars that were mixed in with the following railroads.

Erie, Wabash, CNJ, ACL, Southern, Rock Island, SP, and MoPac ran a mix of 25-30% home and 70-75% others.

PRR, Milwaukee Road, GN, NP, ATSF, and D&RGW ran a mix of 45-55% home and 45-55% others.

The champion is N&W, which ran 78% of its home road equipment. The runners up in second and third place are C&O and L&N with 68 and 66% home road freight cars respectively. At the other end of the spectrum are NKP and B&M with 16 and 17% home road cars. Boston & Albany came in last with only 5 percent (although technically NYC cars should probably also be counted as home road).

About three-fourths of the “other” cars should be from roads that interchanged with your railroad. The right regional mix of cars can really make your train look realistic.

If you primarily model one railroad, like I do with PRR, then freight car purchases can be made with the above data in mind. You can limit what you buy to the cars that will “fit” your region of the country and the time frame for the railroad (my railroad is circa 1953). You can buy less and yet have more fun.

Oh, by the way, in the steam era the Pennsylvania Railroad owned about 30% of the entire nationwide interchange fleet, so you cannot possibly go wrong with having some Pennsy on your roster (a shameless plug). B&O and C&O owned about another 35% of the nationwide interchange fleet, so they were widespread as well.

Now, just how long should that consist be? If there are grades on your railroad then the answer is, “Shorter than you think!” The C&O had to negotiate Cheviot Hill outside Cincinnati, which was at a 1.9-% grade westbound. C&O K-1, K-2, and K-3 Mikado’s, which were some of the heaviest 2-8-2s ever built, could each pull only 11 loaded 50-ton hoppers (these are the short 2-bay hoppers like those made by Weaver) up the grade. This required 50-car hopper trains to have five 2-8-2s, one or two on the lead, one or two cut in the middle, and two trailing pushers. These were not the only locomotives that labored as they pulled the steep grades common to the C&O railroad. Their mighty H6 2-6-6-2 articulated locomotives were only capable of pulling 16 to 17 loaded hoppers up the 2.5% grades common in the coal country of West Virginia. If you have 2% or 3% grades on your layout, then trains should not be very long unless they have multiple engines.

For diesel fans, most first-generation diesel units like the FT, F-3, FA, and RS-3, could only handle about two-thirds of the load of a typical 2-8-2 steamer. The FT diesels used by the Santa-Fe were rated at one loaded car per axle when traversing the Cajon Pass grade. This loading factor limited a FT ABBA set to hauling only 16-cars up its grade. Both steam and diesel motive power could handle about 3 or 4 times as many cars on level terrain as they could on a 2% grade.

If you are interested in replicating a prototypical consist on your layout, fewer cars in the train and less variety in road names can both be very realistic.

By

Frank E. Qualls

Most of the hobbyists today who consider themselves as HiRailers got their start in three-rail trains as children. Many of the days and nights we had off from school during the Christmas season we would lay on the floor near the Christmas tree and watch the trains as they looped around the tree. During the times we played with our trains when they were not around the Christmas tree, we experimented with elevating the curve tracks to enable the trains to pass through them at high speeds without derailing. Superelevating the track was what were doing. Many times these experiments were unsuccessful because we were working with either 0-27 or 0-31 track, which represents a very tight radius. No matter how you looked at these types of track when a trailing caboose or 2500-series Lionel aluminum passenger car passed through them they were being jerked around the curves. The twisting and jerking of our locomotives and cars was even worse when we experimented with reverse or “S” curves using this type of tight curvature track.

Now we HiRailers have acquired huge locomotives like the Allegheny, Big Boy, Challenger and O Scale length passenger cars and freight rolling stock for three-rail. All of this new equipment without a doubt needs wider radius curves and good track work in order to function well on our railroads and look their best. Many of the larger HiRail products require a minimum track radius of 36-inches or 0-72 diameter curves in the common term used in our scale. How does a 36-inch radius or 0-72 diameter curve relate to the size of a prototype curve? To determine this we need to reduce the full-scale radius of a prototype curve to inch-radius in our scale. This is calculated by dividing the prototype radius by a scale factor of 4 for O Scale. A 144-foot radius curve is tight for prototype railroading and a 36-inch radius is tight when one considers the larger equipment we are operating today. Having said all of that, this is where I will briefly discuss in simplified terms transition, superelevated, and reverse curves.

The DC Area Independent HiRailers, the HiRail module group I founded a few years ago is now using new wide radius curve modules with easement transition and superelevation. These 45-degree curve modules have radii of 65.25, 61, and 56.75 inches for diameters of 0-130.5, 0-122, and 0-113.5 respectively. These radii are equal to prototype radii of 261, 244 and 227-feet respectively. These corner modules measure 12-feet across without a straight module between them. Each of the three radii has a three-inch easement or short transition entering and leaving its 90-degree curve. Now you may ask what is an easement or transition curve, and why should I superelevate my curves? What are the benefits I would receive from using them?

As I mentioned earlier in this text, a trailing caboose or passenger car when passing through a tight curve is jerked around it. The same thing happens to a locomotive as it enters or leaves a curve that does not have an easement or transition from the tangent or straight track. The easement provides a short transition between the tangent track and the beginning of the arc of the curve to smooth out the abrupt changes in direction. Instead of the locomotive lurching suddenly from the straightaway into the sharp arc of the curve, the transition eases it gently into a broad spiral until the radius is equal to the true curve itself. The same holds true for the trailing rolling stock or passenger cars as they leave or enter the tangent tracks. This results in the whole train smoothly gliding through the curve as it passes. Easements or transitions on prototype railroads can be many feet long and are not readily replicated to scale on the model railroad due to space constraints. However, HiRailers who have the available space and are planning their layout may want to consider using short easements in their track plan.

Superelevation is achieved when one rail of the track is raised higher than the other rail through a curve. This elevating of the track rail tilts the train as it passes through the curve similar to a racecar going through a banked curve at high speed. This allows a train to travel through the curve fast without derailing. The US Railway Administration measures superelevation in inches and limits US railroads track elevation to a maximum of 6-inches.

Will we HiRailers ever operate our trains at speeds requiring superelevating of our track? I do not think so. However, it is another prototype aspect of model railroading we chose to use on our corner modules because the trains look so good as they tilt a few degrees when passing through the curves.

There are various techniques modelers use to achieve superelevation of their track. One can use small wooden shims, styrene sheets or wire between the track ties and roadbed. We used AWG # 16 stranded wire with its insulation intact between the track and cork roadbed to achieve our superelevation. The wire is positioned between the end of the Gargraves wooden ties and the outside of the outer rail. For the first 3-inches entering or leaving the 45-degree module, the Gargraves trackage remained straight and flat providing easement before beginning the arc of the curve and its superelevation. The superelevating of the trackage is gradual and continues where the two 45-degree modules mate together to complete a 90-degree curve. This provides a smooth transition from one module to the other in either direction without any discontinuity in superelevation. The degree of superelevation you engineer into your trackage depends upon the thickness of the material you use and where you position it under your track. The 16-gauge wire we used measured one-eighth of an inch thick and it has not been determined what the exact scale number is in inches of superelevation we have achieved. Although the result is a 3 to 4 degree tilt in the trains as they pass through our modules. During the weekend of August 5-6 at a Greenberg Train Show in Timonium, Maryland, they worked smoothly and flawlessly. We received many compliments on our track work and the prototypical look of the trains as they passed through the superelevated curves.

Reverse or “S” curves can be very tricky to implement on our railroads or modules. These types of curves consist of two simple curves joined at a common tangent point or short tangent track and curve in opposite directions, such as right to left or vice versa. There are a few problems that can occur when using reverse curves. One of them is wheel binding on long locomotives and cars. This usually occurs when there is not enough tangent track between the reverse curves equal to the length of the longest locomotive or car that passes through them. Also, without a tangent section of sufficient length, there is the unsightly overhang of the long locomotives and cars, which could interfere with rail traffic on adjacent tracks. Additionally, the train is subject to excessive twisting and jerking motion, which can cause derailments when it passes through the reverse or “S” type curves. With this in mind when modeling reverse curves, consider using a tangent track of the proper length between them.

The reverse curve modules I built two years ago whose track radii is 48, 43.75, and 39.5 inches will require a tangent module between them before they are displayed publicly. Based on the Allegheny, Big Boy, and Challenger locomotive sizes the tangent module will have to be at least three feet long if I follow the above reverse curve rule. Using reverse curves in a model or modular railroad track plan, when properly executed, yields the visually pleasing sight of a train that elegantly and gracefully flows through them.

The knowledge of Transition, Superelevated, and Reverse Curves is another prototype aspect of model railroading that HiRailers may want to consider using on their railroads.

Note: The above text on this subject is very simplified. Reference books written on this topic covering all the technical aspects in detail of these types of curves is available if one requires it. However, the above was written in this newsletter as food for thought and to encourage HiRailers interest in this topic.